The fastest unmanned aircraft

The fastest aircraft (unmanned) is the X-43, which set the new world speed record - 12,144 km/h (7,545.9 mph, or Mach 9.835) for a jet-powered aircraft on Nov.16, 2004.

NASA's X-43A research vehicle screamed into the record books again Tuesday, demonstrating an air-breathing engine can fly at nearly 10 times the speed of sound. Preliminary data from the scramjet-powered research vehicle show its revolutionary engine worked successfully at nearly Mach 9.8, or 7,000 mph, as it flew at about 110,000 feet.

The high-risk, high-payoff flight, originally scheduled for Nov. 15, took place in restricted airspace over the Pacific Ocean northwest of Los Angeles. The flight was the last and fastest of three unpiloted flight tests in NASA's Hyper-X Program. The program's purpose is to explore an alternative to rocket power for space access vehicles.
"This flight is a key milestone and a major step toward the future possibilities for producing boosters for sending large and critical payloads into space in a reliable, safe, inexpensive manner," said NASA Administrator Sean O'Keefe. "These developments will also help us advance the Vision for Space Exploration, while helping to advance commercial aviation technology," Administrator O'Keefe said.

Supersonic combustion ramjets (scramjets) promise more airplane-like operations for increased affordability, flexibility and safety in ultra high-speed flights within the atmosphere and for the first stage to Earth orbit. The scramjet advantage is once it is accelerated to about Mach 4 by a conventional jet engine or booster rocket, it can fly at hypersonic speeds, possibly as fast as Mach 15, without carrying heavy oxygen tanks, as rockets must.

The design of the engine, which has no moving parts, compresses the air passing through it, so combustion can occur. Another advantage is scramjets can be throttled back and flown more like an airplane, unlike rockets, which tend to produce full thrust all the time.

"The work of the Langley-Dryden team and our Vehicle Systems Program has been exceptional," said NASA's Associate Administrator for Aeronautics Research J. Victor Lebacqz. "This shows how much we can accomplish when we manage the risk and work together toward a common goal. NASA has made a tremendous contribution to the body of knowledge in aeronautics with the Hyper-X program, as well as making history."

The flight was postponed by one day when repair of an instrumentation problem with the X-43A caused a delay. When the preflight checklist was resumed, not enough time remained to meet the FAA launch deadline of 7 p.m. EST.